Micrometer-gage.



No. 870,403. PATENTED NOV. 5, 1907.

L C. WOERNER.

MIGROMETER GAGE.

APPLICATION FILED FEB. 5. 1907.

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Specification of Letters Patent. I

Patented Nov. 5, 1907;

Application filed Pebruaryfi, 1907. Serial No; 355,789i

To all'whom' it may concern:

Be it known that 1, Louis ilnms'rmn WOERNER, engineer, a citizen of the United States of North America, v residing at 17/20 Huttenstrasse, Berlin, German Empire, have invented new and useful improvements in MicrometerGages, of which the following is a specification. I My invention relates to-a device which can be'readily applied to any micrometer gage and enables dimensions to be read off in millimeters on a micrometer graduated into inches, or inches on a micrometer graduated into millimeters, down to the smallest fractions mm or 61 in), so that one and the same instrument can be employed for exact measurements'both in millimeters and inches. To enable this to be done the hollow cap of the threaded mandrel in addition to the fixed circular graduations for reading off fractions of the one unit of measurement as determined by the pitch of the micrometer screw, is provided with a rotary andsliding scale on which, by means of a stationary index,

fractions of the other unit of measurement, which is not in connection with the pitch of the screw, can be read off, after the approximate measurement in this unit has been first set by means of a second scale on the shank of the micrometer gage. For setting the zero point of the movable scale the cap 01' the mandrel is furnished with vertical graduations corresponding with the second scale on the hollow shank, which vertical graduations, on the micrometer being opened to the required division of the scale on the shank, come below the index. v

in the accompanying drawing the invention is shown applied, by way of example, to a micrometer gage with inch graduations.

Figure l is a side elevation, and Fig. 2 a longitudinal section through the micrometer screw.

it is the body of the gage. of the well-known jaw form, which may be of cast iron. The one end has a tempered steel cheek-piece b'let into it; while the other end has a hollow shank c, forming one piece with the body and containing the micrometer screw. a is the threaded mandrel; e is the nut rigidly fixed in'the shank c. The nut e is provided with slits f and has a thread on the'outside also to receive an adjusting collar g. To the screw mandrel 0." there is connected in wellknown manner a hollow cap in, which fits over the shank c. The latter is provided with both inchgraduations 2' and millimeter graduations j. V is assumed to have 40 threads, so that at the divisions of the inch scale i inch, and with the circular scale or" 25 divisions k of the cap hanother inch,- can-be read off. The cap it is furnished with a number of divisions 2 corresponding with the millimeter scalej on the shank c. in the actual instrument the divisions l 1 ference of the cap 72 is sealed. 1

The micrometer screw are located 2 mms. apart; inthe drawing, however, for the sake of clearness, they are marked at 5 ms. apart.

The divisionsl are so arranged, that, when the lower edge of the cap h: coincides with any of the divisions of the scale 3' the corresponding division I coincides with the edge of an index hereinafter described.

On the cap it there is a rotary, sleeve on, also capable pf slidingin axial direction and provided with graduations 97., which-enable 2 g mms. to be read off in mm. The scale n runs spirally on the sleeve was a millimeter is greater than. inch to which unit the The index 0 for the scale it can be adjusted on the arm p projecting from the bodya.

If new there is to be measured, for instance, in millimeters a piece of work whose thickness is about mms, the zero point of the scale n must first'be adjusted to the division 5 of the graduations Z and the cap it then turned until its lower edge nearly coincides with the division 5 on the scale j; the cap h is then to be turned until the division 5 of the divisions Z and thus also the zero point of the scale 'n coincides with the edge of the index 6. The micrometer is then opened exactly to 5 ms, the movable scale it then enables a further mm. to'be read off. if a piece of work'having a thickness of about nuns. is to be measured, the zero divi sion of the movable scale n must be adjusted to the division 10 of the scale Z and a procedure similar to that already mentioned followed. By the-addition of the movable scale n it is thus possible to read direct from 0-25 mms. in T7156 131111., that is, objects of 0-25 mms., -50 mms;, etc., can be measured exactly to lmm; on the metrical scale.

The sleeve m not only rotates, but also slides in axial direction, so that the rod p may be kept short, to avoid the danger of its getting accidentally broken ed in the workshop. I

Having thusdescrihed'my invention, what I claim is:

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and millimeter scales a micrometer screw working in "the shank and having a hollow cap furnished with circular graduatlons at the edge for reading 01? fractions of the circumin a micrometer gage, a hollow shank provided with unit of measurement determined by the pitch of the 1111- crometer screw,'and vertical divisionecorresponding with the other unit of measurement; and a sleeve rotating and axially sliding on the cap and provided with a scale for reading off fractions of the said second unit of measurement; and an index for the scale on the sleeve; substantially as described. I

' In witness whereof I have'hereunto slgned'my name this 5th day of January 1907, in the presence of two subscribing witnesses.

LOUIS C. WOERN ER.

Witnesses Wonnmnsn, Eisner,

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